Medicament delivery device

ABSTRACT

A medicament delivery device includes a generally elongated tubular housing having opposite proximal and distal parts; a needle shield sleeve slidably and coaxially arranged inside the housing with a proximal part of the sleeve protruding a distance outside the proximal part of the housing; a syringe carrier mechanism having a syringe carrier slidably and coaxially arranged within the needle shield sleeve, a syringe having a stopper, a medicament, and a needle, the syringe being coaxially arranged within the syringe carrier; and a holding member connected to the syringe carrier; a first activator member an a second activator member; a drive mechanism adapted to accumulate a drive force for moving the syringe carrier mechanism in a first step and a second step. The second activator member is arranged within an information device for producing audible, visual, and/or tactile feedback to a user about a completed injection.

CROSS REFERENCE TO RELATED APPLICATIONS

The present application is a continuation application of U.S. patentapplication Ser. No. 14/993,736 filed Jan. 12, 2016, which is acontinuation Ser. No. 14/747,869 filed Jun. 23, 2015, which is acontinuation application of U.S. patent application Ser. No. 13/858,692,filed Apr. 8, 2013, now U.S. Pat. No. 9,302,047, which is a continuationof U.S. patent application Ser. No. 13/500,913, filed Apr. 8, 2012, nowU.S. Pat. No. 8,414,533, which is a 371 of International PatentApplication No. PCT/SE2010/051004, filed Sep. 20, 2010 which claims thebenefit of U.S. Provisional Patent Application No. 61/249,675, filedOct. 8, 2009 and Swedish Patent Application No 0950807-8, filed Oct. 30,2009 the entire contents of which are incorporated entirely herein byreference.

TECHNICAL AREA

The present invention relates to a medicament delivery device and inparticular a device which is capable of providing information regardinga completed medicament delivery step.

BACKGROUND OF INVENTION

There are a number of devices on the market that are capable ofautomatically or semi-automatically delivering doses of medicament,where these devices comprise a number of inter-acting components forobtaining the desired functions.

One type of such delivery devices is an injector capable of deliveringdoses of medicament, having functions such as penetration of thepatient's skin and a subsequent injection of medicament. One such deviceis for example disclosed in the document EP 1349590, comprising anactivation mechanism in the form of a button placed at its distal end.The button may only activate the mechanism if the front end of thedevice is pressed against an injection site. When done so and the buttonis pressed, the penetration mechanism inside the injector is releasedwhereby the needle is pushed into the body of the patient. After this,the injection is performed.

When the injection is completed, the patient withdraws the injector withthe needle from the injection site, whereby a needle shield is pushedforward until it surrounds the needle and is then locked.

With an injector of the above described type there is often a desire forthe user to know when the injection is completed and it is safe toremove the injector. A few solutions of informing the user of the statusof the injection have been developed.

U.S. Pat. No. 6,221,046 describes an injection device having an “end ofinjection click: including an extension of a flexible tab of a dose dialmechanism. The tab with the extension falls into a groove in thehousing, causing an audible click at the end of injection. US2004/0097883 discloses a similar end of injection click solution.

However, even if some solutions have been presented regarding informinga user of a medical delivery device, there is still room forimprovements, especially regarding the delivering step of a medicaldelivery device.

BRIEF DESCRIPTION OF INVENTION

The aim of the present invention is to remedy the drawbacks of the stateof the art devices.

This aim is solved according to the present invention by a medicamentdelivery device according to the features of the independent patentclaim.

Preferable embodiments form the subject of the dependent patent claims.

According to a main aspect of the invention it is characterised by amedicament delivery device comprising a generally elongated tubularhousing having opposite proximal and distal parts; a needle shieldsleeve slidably and coaxially arranged inside the housing and wherein aproximal part of said sleeve protrudes a distance outside the proximalpart of the housing; a syringe carrier mechanism comprising a syringecarrier slidably and coaxially arranged within the needle shield sleeve,a syringe comprising a stopper, a medicament and a needle, wherein saidsyringe is coaxially arranged within said syringe carrier, and a holdingmember connected to the syringe carrier; a first activator memberslidably and coaxially arranged within the housing and connected to saidneedle shield sleeve; a second activator member slidably and coaxiallyarranged within the first activator member; a drive mechanism slidablyand coaxially arranged within the second activator member and releasiblyconnected to the holding member and to the second activator member,wherein said drive mechanism is adapted to accumulate a drive force formoving said syringe carrier mechanism in a first step for penetratingthe needle into an injection site and to move said stopper in a secondstep for expelling the medicament through the needle, and wherein saiddrive mechanism is controlled by the first and the second activatormembers; wherein said second activator member is arranged withinformation means arranged to cooperate with corresponding interactingmeans arranged on the distal part of the elongated tubular housing afterthe medicament is completely expelled such that a remaining drive forceof the accumulated drive force in the drive mechanism forces the secondactivator member to be displaced towards the distal part of theelongated tubular housing for producing audible, visual and/or tactilefeedback to a user about a completed injection.

According to another aspect of the invention, said information meanscomprises an information member attached to a distal transversal endwall of the second activator member, and said corresponding interactingmeans comprises an opening arranged on a distal wall of the distal partof the elongated tubular housing.

According to a further aspect of the invention, said information memberis provided with a characteristic colour.

According to yet another aspect of the invention, the drive mechanismcomprises a plunger rod arranged to act on the stopper inside saidsyringe, and a pre-tensioned first compression spring having a forcecapable of urging said plunger rod to move in a first step said syringecarrier mechanism for penetrating the needle into an injection site andin a second step said stopper for expelling the medicament through theneedle.

According to another aspect of the invention, the plunger rod isslidably and coaxially arranged within the second activator member andthe pre-tensioned first compression spring is coaxially arranged withinthe plunger rod between a proximal end wall of the plunger rod and thedistal transversal end wall of the second activator member.

According to a further aspect of the invention, the second activatormember comprises flexible tongues having annular inwardly directedledges, wherein the holding member comprises flexible tongues havingannular inwardly directed ledges, and wherein the plunger rod comprisesa circumferential groove having a mutual shape as that of the ledges ofthe second activator member and as that of the ledges of the holdingmember so that the annular inwardly directed ledges of the secondactivator member and the radial inwardly directed ledges of the holdingmember fit into the groove.

According to yet another aspect of the invention, the plunger rodarranged to be held against the force of the pre-tensioned firstcompression spring by the inwardly directed ledges of the tongues of thesecond activator member situated in the groove of the plunger rod, andby the first activator member which surrounds and prevents the tonguesfrom moving radially outwards.

According to another aspect of the invention, the device furthercomprises a pre-tensioned second compression spring having an annularproximal end resting on a second annular ring of the first activatormember and an annular distal end resting on the proximal surface of stopledges of the second activator member.

According to a further aspect of the invention, the needle shield sleeveand the first activator member connected to it are arranged to be movedcoaxially and distally in relation to the housing and to the secondactivator member when the proximal part of said needle shield sleeve ispressed against the injection site for allowing the inwardly directedledges of the tongues of the second activator member to be released fromthe groove of the plunger rod, such that the force form thepre-tensioned first compression spring urges said plunger rod to move ina first step said syringe carrier mechanism and in a second step saidstopper.

According to yet another aspect of the invention, the second activatormember is arranged to be coaxially and distally moved by a remainingforce of the pre-tensioned first compression spring after the distal endof the plunger rod pass the ledges of the second activator member suchthat the tongues are radially moved inwards, whereby the distaltransversal end wall of the second activator member strikes against adistal wall of the distal housing part giving an audible signalindicating that the injection has been completed and that the device canbe safely removed from the injection site.

According to another aspect of the invention, said information memberprotrudes trough said opening becoming tactile and/or visible to providetactile and/or visual information indicating that the injection has beencompleted and that the device can be safely removed from the injectionsite when the second activator member is coaxially and distally moved.

According to a further aspect of the invention, the needle shield sleeveand the first activator member are arranged to be coaxially andproximally moved in relation to the housing and to the second activatormember by a force from the pre-tensioned second compression springacting on the first activator member and thus on the needle shieldconnected to it for covering the needle, when the proximal part of theneedle shield sleeve is removed from the delivery site.

According to yet an aspect of the invention, the first activator membercomprises ribs on its inner surface arranged to interact with aband-shaped part of the second activator member after the needle shieldsleeve and the first activator member are coaxially and proximallymoved, for preventing any attempts to push the needle shield sleevedistally into the device.

There are a number of advantages with the present invention. Because theuser is provided with information regarding the completed injection,he/she can safely remove, the medicament delivery device from thedelivery site, knowing that the injection is completed.

An advantage is that the remaining force of the compression spring meansused for penetration and injection is used for providing the informationto the user.

In this aspect the information could be visual, i.e. that the user canactually see that the injection has been performed through an opening inthe device, like a window or a passage. Further in order to enhance thevisibility the indicator could have a bright and/or different colourthan the rest of the device.

Further the information member could also be made to protrude throughthe housing of the device, thereby also providing tactile information tothe user as well as visible.

In addition to the visual and/or tactile information the deviceaccording to the invention could be audible in that there is a distinctsound when the injection has been performed.

A preferable arrangement of the information member is arranged at thedistal end of the device, which facilitates the design since it does notrequire any more components than the second activator member in order toprovide an information function.

In all several ways of positively indicating the performed injection isobtained with the present invention.

These and other aspects of, and advantages with, the present inventionwill become apparent from the following detailed description of theinvention and from the accompanying drawings.

BRIEF DESCRIPTION OF DRAWINGS

In the following detailed description of the invention, reference willbe made to the accompanying drawings, of which

FIGS. 1a, b show cross-sectional side views of a medicament deliverydevice according to the present invention, where FIG. 1b is taken 90° inrelation to FIG. 1 a;

FIG. 2 is an exploded view of the medicament delivery device of FIG. 1,and

FIGS. 3-6 are cross-sectional side views of the medicament deliverydevice according to the present invention in different functionalstates.

DETAILED DESCRIPTION OF THE INVENTION

In the present application, the term “distal part/end” refers to thepart/end of the device, or the parts/ends of the members thereof, whichunder use of the device, is located the furthest away from a deliverysite of a patient. Correspondingly, the term “proximal part/end” refersto the part/end of the device, or the parts/ends of the members thereof,which under use of the device is located closest to the delivery site ofthe patient.

The medicament delivery device, e.g. an auto-injector as seen in FIG. 1,comprises a generally elongated tubular housing having opposite proximal10 and distal 12 parts. The proximal housing part 10 is arranged withelongated openings 14 for viewing a syringe 16 which contains a liquidmedicament, FIG. 2. The distal part is arranged with engagement means asannular recesses e.g. on its inner surface adapted to interface withcorresponding engagement means on e.g. the proximal outer surface of theproximal part.

The device further comprises a needle shield sleeve 20, FIG. 2,hereinafter named needle shield, wherein said needle shield comprises aproximal part 22 having a certain diameter and a distal part 24 having adiameter larger than the proximal part, where these parts are joined byan intermediate conical part 26, FIG. 2. Two elongated grooves 28 arearranged along the needle shield, on opposite sides of the needleshield, also for viewing the syringe 16, FIG. 2. On the inner surface ofthe conical part 26, a circumferential ledge 30 is arranged, FIG. 2. Atthe distal end of the needle shield two openings 32 are arrangedopposite each other, where each opening is arranged with a somewhatinwardly projecting, flexible, tongue 34, FIG. 2. The needle shieldsleeve 20 is slidably and coaxially arranged inside the housing and theproximal part of said sleeve protrudes a distance outside the proximalpart of the housing.

The device also comprises a syringe carrier mechanism comprising asyringe carrier 36 slidably and coaxially arranged within the needleshield sleeve; the syringe 16 comprising a stopper 92, the medicamentand a needle, wherein said syringe is coaxially arranged within saidsyringe carrier; and a holding member 46 connected to the syringecarrier.

The syringe carrier 36 has the form of a general tubular body and theproximal part of the syringe carrier is arranged with a neck portion 38of lesser diameter, FIG. 2 Adjacent the neck portion cut-outs have beenmade on either side to form guide surfaces 39. These surfaces cooperatewith corresponding shapes of the inner surface of the needle shield inorder to obtain a stop mechanism against rotation of the syringe carrierrelative the needle shield. The distal end of the syringe carrier isarranged with two distally extending tongues 40, where each tongue isarranged with an opening 42 and an inwardly directed ledge on the distaledge of each opening, FIG. 2. The syringe carrier is further arrangedwith radial inwardly directed flanges on its inner surface in order toobtain a space between the syringe carrier wall and the syringe 16 to beplaced inside.

The holding member 46, FIG. 2, comprises a ring-shaped body 48 having anannular ledge 50 arranged around its circumference and a number offlexible tongues 52 directed towards the distal end of the device andwherein each tongue 52 is arranged with radial inwardly directed ledges54, FIG. 1 b.

The device also comprises a first activator member 56 which is slidablyand coaxially arranged within the housing and connected to the needleshield sleeve 20 as will be described below, which has a tubular shapeand which comprises a proximal end with a conical part 58 ending in aledge 60 on its outer surface, FIG. 2. At a distance from the ledge 60,a first annular ring 62 is arranged on the outer surface, FIG. 2. Asecond annular ring 64 is also arranged a further distance from theledge 60.

The device further comprises a second activator member 66 which isslidaby and coaxially arranged within the first activator member 56 andwhich has a mainly tubular shape. A number of longitudinally directedcut-outs 68 are arranged along the proximal outer surface of the secondactivator member so as to form flexible tongues 70, FIG. 2. The proximalend of each flexible tongue 70 has an inclined transition surface whichmeets with a band-shaped part 72 with enlarged diameter, FIG. 3. On theinner surface adjacent the transition surface, an annular inwardlydirected ledge 74 is arranged, FIG. 1 b. Further, the second activatormember 66 is arranged with information means arranged to cooperate withcorresponding interacting means arranged on the distal part of theelongated tubular housing. Said information means comprises aninformation member 78 attached to a distal transversal end wall 76 ofthe second activator member, and said corresponding interacting meanscomprises an opening 80 arranged on a distal wall 82 of the distal partof the elongated tubular housing, FIG. 1 a.

The device also comprises a drive mechanism which is slidably andcoaxially arranged within the second activator member 66, and which isreleasibly connected to the holding member and to the second activatormember, said drive mechanism being controlled by the first and thesecond activator members as will be described below. The drive mechanismis adapted to accumulate a drive force for moving the syringe carriermechanism in a first and a second step and, after completely expellingthe medicament, to force the second activator member towards the distalpart of the elongated tubular housing for producing audible, visualand/or tactile feedback to a user about a completed injection.

The drive mechanism comprises a plunger rod 90 arranged to act on thestopper 92 inside said syringe 16, and a first compression spring 94that is pre-tensioned to have an accumulated force capable of urgingsaid plunger rod to move said syringe carrier mechanism in a first stepfor penetrating the needle into an injection site and to move saidstopper in a second step for expelling the medicament through theneedle. The plunger rod is slidably and coaxially arranged within thesecond activator member and the pre-tensioned first compression spring94 is coaxially arranged within the plunger rod between a proximal endwall 98 of the plunger rod and the distal transversal end wall 76 of thesecond activator member. Further a guide rod 100 is arranged inside thefirst compression spring 94, FIG. 1 a.

The plunger rod 90 is formed as a tube with an outer diameter somewhatsmaller than the inner diameter of the syringe body to be used. Theplunger rod 90 is arranged with a circumferential groove 96 having amutual shape as that of the ledges 74 of the second activator member 66and as that of the ledges 54 of the holding member 46 so that theannular inwardly directed ledges 74 of the second activator member 66and the radial inwardly directed ledges 54 of the holding member 46 fitinto the groove 96, FIG. 1 b.

The device further comprises a pre-tensioned second compression spring102 having an annular proximal end resting on the second annular ring 64of the first activator member 56 and an annular distal end resting onthe proximal surface of stop ledges 104 of the second activator member66, FIG. 2.

The function of the device according to the invention will now bedescribed in connection with the FIGS. 3-6.

When the device is assembled, the distal housing part 12 is fixedlyattached to proximal housing part by suitable engagement means formingthe elongated tubular housing and the first and the second activatormembers are coaxially movable relative each other. However, when thedevice is in a non-activation position, the plunger is held against theaccumulated force of the pre-tensioned first compression spring 94 bythe inwardly directed ledges 74 of the tongues 70 of the secondactivator member 66 situated in the groove 96 of the plunger 90, and bythe first activator member 56 which surrounds and prevents the tongues70 from moving radially outwards. Further the ledges 54 of the holdingmember 46 are also arranged in the groove 96, FIG. 1b . The inwardlydirected ledges on the distal edge of each opening 42 of the syringecarrier 36 pass the distal end surface of the annular ledge 50 of theholding member 46 for connecting the syringe carrier to the holdingmember, and at the same time the tongues 34 of the needle shield 20 fitthe distal surface of the ledge 60 of the first activator member 56 forconnecting the needle shield to the first activator member.

The needle shield sleeve and the first activator member connected to itare arranged to be moved coaxially and distally in relation to thehousing and to the second activator member against the force of thepre-tensioned second compression spring 102, when the proximal part ofsaid needle shield sleeve is pressed against the injection site, FIG. 3.When the first activator member moves distally, the band-shaped part 72of the second activator comes out from the surrounding of the firstactivator member 56, FIG. 3 and the resilient properties of the tongues70 of the activator means allows the proximal end of the tongues 70 toflex radially outwards, causing the ledges 74 to be released from thegroove 96 of the plunger rod 90. However, the ledges 54 of the holdingmember 46 are still in the groove 96 of the plunger rod and with theproximal end surface against the distal end of the syringe carrier 36,whereby the accumulated force from the pre-tensioned first compressionspring urges said plunger rod to move in the first step said syringecarrier mechanism, whereby a penetration of the needle into theinjection site is performed.

When the syringe carrier has reached its most proximal position it isforced to a stop. However the accumulated force of the pre-tensionedfirst compression spring acting on the plunger rod is so high that theledges 54 of the holding member 46 are forced out of the groove of theplunger rod.

The accumulated force from the pre-tensioned first compression springcontinues to urge said plunger rod to move in the second step saidstopper inside the syringe and the liquid medicament is injected intothe patient until the stopper reaches the inner proximal end of thesyringe, FIG. 4. After the liquid medicament has been injected and thedistal end of the plunger rod has passed the ledges 74 of the secondactivator member 66, the tongues 70 are radially moved inwards. Becausethe pre-tensioned first compression spring is also acting on the innersurface of the distal transversal end wall 76 of the second activatormember 66 and has a remaining accumulated force, the second activatormember 66 is moved distally until the outer surface of the distaltransversal end wall 76 of the second activator member 66 strikesagainst the inner surface of the distal wall 82 of the distal housingpart 12 giving an audible signal to the patient indicating that thedelivery e.g. the injection has been completed and that the device canbe safely removed from the injection site, FIG. 5.

Further, the protrusion 78 of the second activator member 66 protrudesthrough the opening 80 becoming tactile and/or visible to providetactile and/or visual information indicating that the injection has beencompleted, FIG. 5, and that the device can be safely removed from theinjection site when the second activator member is coaxially anddistally moved, e.g. if for instance the users finger is positioned onthe end wall 82 and in addition a visual indication in that theprotrusion 78 is visible through the passage 82. In order to enhance thevisibility, the protrusion could be arranged with a bright colour,differing from the colour of the rest of the device.

The needle shield sleeve and the first activator member are arranged tobe coaxially and proximally moved in relation to the housing and to thesecond activator member by a force from the pre-tensioned secondcompression spring 102 acting on the first activator member and thus onthe needle shield connected to it for covering the needle, when theproximal part of the needle shield sleeve is removed from the deliverysite FIG. 6.

The first activator member 56 comprises ribs (not shown) on its innersurface arranged to interact with a band-shaped part 72 of the secondactivator member 66 after the needle shield sleeve and the firstactivator member are coaxially and proximally moved, for preventing anyattempts to push the needle shield sleeve distally into the device,which prevents unintentional needle sticks.

It is to be understood that the embodiment described above and shown inthe drawings is to be regarded only as a non-limiting example of theinvention band that it may be modified in many ways within the scope ofthe patent claims.

The invention claimed is:
 1. An injection method comprising: arranging asyringe carrier within a tubular housing, configuring the syringecarrier to carry a syringe, the syringe comprising a stopper, amedicament, and a needle, slidably arranging a needle shield sleeve inthe tubular housing and protruding a distance outside of the tubularhousing, arranging a plunger rod to act on the stopper of the syringe,arranging a first compression spring to drive the plunger rod in aproximal direction, connecting a first activator member to the needleshield sleeve such that the first activator member moves with the needleshield sleeve, releasably holding the plunger rod with a secondactivator member prior to an injection of the medicament containedwithin the syringe, providing information that an injection of themedicament contained within the syringe has been completed with aninformation member, and releasably holding the first activator memberand the needle shield sleeve with the second activator member such that(i) the second activator member limits proximal movement of the firstactivator and the needle shield sleeve prior to the injection and (ii)the second activator member allows proximal movement of the firstactivator and the needle shield sleeve after the injection has beencompleted.
 2. The method of claim 1, wherein releasably holding thefirst activator member and the needle shield sleeve with the secondactivator member is after the needle shield sleeve and the firstactivator member have moved distally.
 3. The method of claim 2, furthercomprising: releasing the first activator member and the needle shieldsleeve after the injection.
 4. The method of claim 3, wherein releasingthe first activator member and the needle shield sleeve is after theplunger rod moves the stopper contained inside the syringe and themedicament is injected after the stopper reaches an inner end of thesyringe.
 5. The method of claim 1, further comprising: resting anannular proximal end of a second compression spring on the firstactivator member, and resting an annular distal end of the secondcompression spring on a proximal surface of the second activator member.6. The method of claim 5, further comprising moving the needle shieldsleeve and the first activator member in a distal direction in relationto the tubular housing against the second compression spring.
 7. Themethod of claim 1, further comprising: providing tactile informationthat an injection has been completed.
 8. The method of claim 1, furthercomprising: providing visual information that an injection has beencompleted.
 9. The method of claim 1, further comprising: slidablyarranging the second activator member with the first activator member.10. The method of claim 1, further comprising: coaxially arranging thesecond activator member with the first activator member.
 11. The methodof claim 9, further comprising: arranging a plurality of longitudinallydirected cut-outs along a proximal outer surface of the second activatormember.
 12. The method of claim 11, further comprising: forming aplurality of flexible tongues with the plurality of longitudinallydirected cut-outs.
 13. The method of claim 12, further comprising:providing an inclined transition surface on a proximal end of at leastone of the plurality of flexible tongues.
 14. The method of claim 13,further comprising: meeting the inclined transition surface with a bandshaped part with an enlarged diameter.
 15. The method of claim 14,further comprising: configuring the inclined transition surface toreleasably hold the first activator member and the needle shield sleeveafter the first activator member and the needle shield sleeve move inthe distal direction.
 16. The method of claim 1, further comprising:providing the second activator member with at least one radiallyextending directed ledge, providing the plunger rod with a groove, andconfiguring the at least one radially extending directed ledge to fitinto the groove of the plunger rod.
 17. The method of claim 16, furthercomprising: arranging the at least one radially extending directed ledgeat an end of at least one flexible tongue.
 18. The method of claim 1,further comprising: slidably and coaxially arranging the syringe carrierwithin the needle shield sleeve.
 19. The method of claim 1, furthercomprising: defining an inner cavity of the plunger rod.
 20. The methodof claim 19, further comprising: coaxially arranging the firstcompression spring within the inner cavity of the plunger rod.
 21. Themethod of claim 1, wherein the first compression spring is pre-tensionedwith a predetermined amount of force, wherein the method furthercomprises driving the plunger rod using a first portion of thepredetermined amount of force of the first compression spring to injectthe medicament, and wherein providing the information that the injectionhas been completed with the information member is performed using asecond portion of the predetermined amount of force after driving theplunger rod using the first portion of the predetermined amount offorce.